Currently, in network deployment of a wireless communications network, one base station has two different cells, and a terminal may maintain connection to the two different cells of the base station simultaneously. Of two cells that maintain connection to a same terminal, one is a primary serving cell, and the other is a secondary serving cell. In a communication process between the primary serving cell and the terminal, an FDD (frequency division duplex) manner may be adopted, and a TDD (time division duplex) manner may also be adopted; in a communication process between the secondary serving cell and the terminal, the TDD manner is adopted.
In the prior art, when a base station performs TDD configuration on a secondary serving cell, the base station determines TDD configuration information for the secondary serving cell, and sends, by using a primary serving cell, a TDD configuration information of the secondary serving cell to a terminal; and after receiving the TDD configuration message of the secondary serving cell, the terminal determines an uplink-downlink subframe allocation of the secondary serving cell, that is, the terminal determines a subframe number used when a signal is sent to the base station and a subframe number used when a signal sent by the base station is received, so that the terminal and the secondary serving cell communicate with each other according to the uplink-downlink subframe allocation of the secondary serving cell.
However, in new network deployment, it is possible that a primary serving cell and a secondary serving cell of a terminal belong to different base stations, where a base station to which the primary serving cell belongs is a primary base station, a base station to which the secondary serving cell belongs is a secondary base station. When a primary serving cell and a secondary serving cell of a terminal belong to different base stations, TDD configuration of the secondary serving cell cannot be completed by using a method in the prior art.